Courvoisier Frères "Mobilis", La Chaux-de-Fonds, Movement No. 104400, Case No. 3018, 53 mm, 99 g, circa 1900

A "Poor Man's Tourbillon" according to the Swiss patent no. 30754 of Paul Loichot with club-tooth lever escapement
Case: silver, engine-turned. Dial: silvered. Movm.: full plate movement, U.S. Pat. appl. for D.R.P. ang. Pat. N. 7888/1905, Brevettato R.A.208.N.232, Btè S.G.D.G. 30754, screw compensation balance.

Courvoisier Frères
Brothers Henri-Louis and Philippe Auguste Courvoisier traded from 1842 on under the name "Courvoisier Frères". When more brothers joined the partnership in 1882, they changed the company name to "Courvoisier Fils". Specialising in high quality watches, they were commissioned by the city of La Chaux-de-Fonds to create a watch for the Prussian King William IV; at the time this ultra-flat watch was supposedly the thinnest in the world. The tourbillon movement invented by the Swiss Paul Loichot (which he turned in the case so it would be visible face-sided) was patented for the Courvoisier brothers on July 4th, 1905 under the number 19062 and the name "Mobilis".